
Meshino has joined from Manchester City after spending last year with Scottish Premiership side Heart of Midlothian, where he scored three times in 21 appearances as the club was relegated to the second tier.
Rio Ave finished fifth in last year’s Portuguese league and will play in the preliminary rounds of the UEFA Europa League in the coming season. The club have an option to make the deal permanent at the end of the loan spell.
"I hope I can help the team reach the main draw of the Europa League, and on top of that contribute a lot of goals and assists," Meshino said in a video message posted on the club’s Twitter account.
The midfielder, who started his career with Gamba Osaka before signing for Manchester City last year, was a member of Hajime Moriyasu’s squad that represented Japan at the AFC U23 Championship in Thailand in January.
Meshino played twice for his country in that competition, scoring in Japan’s opening defeat against Saudi Arabia, and he was unable to prevent his team exiting the tournament at the end of the group phase.
